Nonlocal absorption of gold and silver nanostructures is studied with ADE-FDTD method. A Drude-Lorentz model of metal material is discretized and iterative coefficients are deduced in detail. Absorption characteristics of one-, two- and three-dimensional gold and silver nanostructures are studied. It shows that the nonlocal layered films conforms to the equivalent medium theory. In one- and two-dimensional cases, nonlocal absorption peaks are related to the nano scale and have no relation with the material. The nonlocal absorption properties of three-dimensional nanostructures are related to nanoscale, and to material as well. Nonlocal effect of three-dimensional nano structures is the strongest, and the blue shift of the absorption peak is larger. Therefore, three-dimensional gold and silver nano structures are expected to play a role in nano devices.

A first-principles implicit simulation program, Implicit Stratonovich Stochastic Differential Equations (ISSDE), is constructed for stochastic differential equations which describes plasmas with Coulomb collision. Basic idea of the program is stochastic equivalence between Fokker-Planck equation and Stratonovich SDE. Implicit discrete method guarantees numerical stability and conservation of kinetic energy. ISSDE is built with C++ language, and is designed to possess standard interfaces and extendible modules. Slowing-down processes of electron beams in both unmagnetized and magnetized plasmas are studied, which shows correctness of ISSDE. It provides a powerful tool for collisional plasmas studies.

To understand fantastic multiferroicity of CoCr₂O₄, a Heisenberg spin model on three-dimensional spinel lattice was constructed. In the model, we considered multiple magnetic interactions including nearest-neighbor A-A, A-B, B-B couplings as well as next-nearest-neighbor interaction among B sites. Monte Carlo simulation is employed to obtain magnetoelectric quantities. Influences of exchange couplings on magnetoelectric behaviors are emphatically investigated under rotation of magnetic field. It is found that macroscopic magnetization and polarization stem mainly from contributions of B1 ions. With varying exchange couplings of A-A interaction and next-nearest-neighboring B-B interaction among B-site ions, B-site ions exhibit prominent magnetoelectric responses, while A-site ions remain unchanged. It indicates distinct differences between symmetry and magnetic interaction environment for A-site and B-site ions in spinel lattice.

To obtain reasonable scales and grid requirements of computational zone, water flow in 5×5 fuel pins assembly was simulated adopting incompressible N-S equations, standard k-ε turbulent model and SIMPLE algorithm. By comparing pressure drop, velocity and its vertical component at different planes perpendicular to fuel pins, with relative error smaller than 5%, conclusions were obtained. Length of inlet part and outlet part of computational domain should be about 2.0 times and 2.3-2.8 times of space between two spacer. Polyhedral mesh should be adopted and its scale should be smaller than 0.35 mm in zone between spacer as smooth pin zone adopt structured grid with 0.3 mm-0.5 mm dimension.

In order to improve efficiency and resolution of inversion and computation in concrete tomography, we propose a probability weighted conjugate gradient algorithm, in which weight is added on imaging unit instead of equation. IART algorithm is adopt to determine weight factor and initial value. Simulation examples and a real physical experiment show that the algorithm is of fast convergence, feasibility and validity.

Riemann problems are constructed at interface in front tracking (FT) method for multi-fluid flows to study application of shock limiter.In gas-gas and gas-water problems,shock limiter parameter is selected about 0.3 considering average conservation error,L₁ error and strength of the shock.It is indicated that in order to obtain better solutions the back shock wave should be selected as an original state for Riemann problems at the interface as a shock is close to a material interface.

Propagation of light in a supersonic flat turbulence boundary layer is numerically analyzed. The flow characteristics are studied according to the optic wave-front variance. The mass-weight averaging N-S equations are adopted as the governing equations of flow, and a two-equation turbulent model is employed. Light propagation is described by paraxial wave equations and solved by a phase-screen method combined with the FFT technique, Light intensity distribution and phase aberrations are given in order to show the optic aberrations as well as the flow characteristics.

The stability analysis and transition prediction are proceeded for one-order compression ramp,which is the valuable configuration for the hypersonic vehicles.The finite volume method is used to solve the NS equations to get the basic flow field.The solution of the eigenvalue problem is obtained by using the linear stability theory under the assumption of local parallel flows.The first mode and the second mode unstable waves are found at the Mach number of 6.With the relation of the temporal and spatial amplification rates,the transition position is predicted by the EN method.

It is shown how attenuation changes with porosity according to Biot theory.Frame modulus versus porosity relation based on experiment data set is adopted.It is found that attenuation coefficient of the fast compressional wave increases first,then decreases smoothly to zero,and finally increases sharply.To explain the zero-attenuation phenomenon,the relative motion between the solid frame and the pore fluid is studied when an elastic wave propagates in a fluid-saturated porous medium.It is shown that there can be porous formations that satisfy the dynamic compatibility condition.When a fast compressional wave propagates in such formations,there will be no relative motion between the two constituent phases,and thus no attenuation.A related revelation from this mechanism is about electrokinetic effect in porous media:there can be no coupling between the fast compressional wave and the electromagnetic wave in a dynamically compatible medium,even when there are surplus charges in the saturating fluid of the formation.

Numerical method for stability analysis and transition prediction for supersonic flow around a blunt cone is investigated. In order to meet the required accuracy of the numerical values in the basal flow field, the result of the flow field is obtained by solving Euler equations where the pressure attribution on the surface of the cone is used as the outer edge pressure attribution of the viscous boundary layer. The Rayleigh inverse-iteration method and boundary layer asymptotic expansion method are used to solve the blunt cone boundary layer stability equation to get reliable boundary layer transition data. This method improves the numerical precision, and saves the computation time. It is also useful for stability analysis of blunt cone supersonic flow.

A new computing method is proposed for solving inverse problem of one-dimensional wave equation on seismic prospection by using difference-discrete regularization method. The numerical results of simulation are given and show the method is faster convergence and more powerful noise-resistance.

Photoelectron outgoing wave emitted from core state of excited atom will be scattered by near neighbor atoms.Scattered waves (object waves) which contain structural information of the environment around the excited atom interfere with the original one(reference wave)which propagates directly to the detector,and then a diffraction pattern,i.e.a photoelectron hologram,will be created.A complete 3 D image of the structure surrounding the emitter with at omic resolution can be reconstructed.This paper gives computer simulation for ca lculat ing photoelectron holograms of small atomic clusters on c(2×2) S/Ni(100) surface,in metal copper,and on puckered Cu2O plane of superconductor YBCO.

An alternating group explicit iteration method of high accuracy is constructed for solving Burgers equation on the basis of physical sense of convection speed,and its stability and convergence are analysed by the linear method.Numeical results of the model problem are given.

With the mesoscale model being used as the dynamical frame, and coupled with the cloud model of explicit scheme, a numerical simulation is conducted on the macro parameters of cloud fields, water vapour of cloud and size-distribution of the spectrum of cloud particles, based on which the application of cloud model in aviation is also investigated.

The Singular Spectrum Analysis method,especially on the fundamental property of identifying the oscillatory compo-nents,is described.It is applied to a 30-year surface temperature series of east-southem china with a windows length of 100 days.Two main low-frequency oscillations with period of 35-40day and about 20 days are found to be robust,accounting for about 90% of total variance in the relevant frequency band.

Under the general initial-boundary-value condition and additional condition, the methods for solving problem of one-dimensional wave equation is discussed. The inverse problem is reduced to an ill-posed non-linear integral system. Tikhonov's regularization method overcomes the difficulty of inverse problem and has a good numerical stability. The Numerical results show that the method is feasible and effective.

This paper presents a new version of the generalized pulse-spectrum technique,which is popularly used for solving the inverse problem of differential equations. This version has the property of immunizing noises. The skill of aving computing time is also given in the process of choosing regularign parameters. In the end, the application on the inverse problem is seismic prospection is discussed, the numerical result of simulation is given.

In this paper, Discrete Newton Method for solving nonlinear operator equations and Tikhonov's regularization method for solving linear ill-posed problems are combined into a stable iterative scheme for solving nonlinear operator equations with hard computed and ill-conditioned derivatives. The results of convergence analyses and error estimates are ob-tained. The application of this method for solving the inverse problem on remote sensing of the thermal conductivity in the nonhomogeneous material is demonstrated. It is shown by numerical simulations that this method is feasible and effective.

This paper analyses the main cause of the humidity effect in spelaeos, i.e. the mixture of humid air advection. It also points out the effectiveness of using sealing door separation to prevent humidity. In the end, there is a research into the measures of spelaeon antihumidity.

This paper, based on the characteristics of the Three Gorges Cascade Hydroelectric System, establishes a new short term economic scheduling network model for a cascaded hydroelectric system that transmits power to multiregions. A method combined with linear and nonlinear minimum cost network flow algorithms is used to solve the problem of load dispatch among the cascaded plants. In this paper, the short path algorithm with the data structure which is marked to arcs of the network saves the computational time and the storage space. The result that is computed on the microprocessor IMB PC/XT with FORTRAN language programs indicates that the model and the algorithm is the paper are correct.